QOS in Wide Area Networks

For mission-critical voice, data, and video traffic, yesterday's "best effort" Internet delivery is no longer enough. The solution: Quality of Service (QOS)-a family of techniques that enable service providers and companies to guarantee specific levels of wide area network performance. In this book, leading telecommunications consultant Uyless Black explains all aspects of WAN quality of service, giving communications professionals all the information they need to implement them, and deliver services based on them. Coverage includes: How QOS works-and why it is crucial to networks that must deliver integrated voice, data, and video traffic Implementing QOS in IP, ATM and frame relay environments Leveraging QOS capabilities built into IPv4 and IPv6 Mastering the Resource Reservation Protocol (RSVP), Real-Time Transport Protocol (RTP), and DiffServ Establishing and enforcing QOS guarantees in business networks Understanding Layer 4 QOS-capable devices that prioritize data traffic using transport-layer criteria Quality of Service in Wide Area Networks also includes detailed coverage of using QOS for delivery of integrated services; and of Multiprotocol Label Switching (MPLS), the new Internet standard that promises to seamlessly integrate routing control, while increasing network scalability and reducing complexity.

Whether you're a service provider, corporate telecommunications professional, or internetworking product developer, you need to understand QOS technologies-and with this authoritative guide, you will.

Table of contents

1. Introduction.
Why QOS? What is qos? Congestion: Death Knell to Effective QOS. Provisioning and Supporting QOS. Flow Longevity. Cooperative and Noncooperative Networks. The Internet: An Noncooperative Network. Applications' Natural Bit Rate. The QOS Models. Functional Equivalence Class (FEC). Scope of QOS Service and QOS Domains. Qualitative and Quantitative Service Levels. Genesis of QOS: X.25. Service Level Agreements (SLAs). Policy-Based Networking. SLA Monitoring Points. Summary.
Appendix 1:A Characteristics of the Internet.
Round-Trip Time (RTT). Traffic Loss. Fixed vs Dynamic Routing.
2. QOS Concepts and Operations.
Statistical Multiplexing. Congestion Problems. Flow Control Mechanisms. Explicit and Implicit Flow Control. Problems with Internet Flow Control Services. Solutions to the Problem. Congestion, Traffic Control, and Connection Admission Control. Arrival Rate and Traffic Load. Queue Management Operations. Operations at the Final Destination. Buffer Size, Packet Size, and Traffic Loss. Data “In Flight”. Error Recovery in High-Speed Networks. Monitoring and Traffic Tagging. Associating Labels with QOS Operations. Controlling Data Traffic. Summary.
3. QOS Evolution.
Network Interfaces (Reference Points). Value of the Interface Concept. Evolution of the Interface/Reference Point Concept. The QOS Layered Model. Connection-Oriented and Connectionless Interfaces. QOS in Connection-oriented and Connectionless Networks. Connection Management vs Payload Integrity Management. Payload Integrity Management. Evolution of Payload Integrity Services. Link-by-Link Operations. UNI Operations. End-to-End Operations. Evolution of Switching and Relaying Technologies. Circuit Switching. Message Switching. Packet Switching. Frame Relay. Cell Relay. Network Availability: A Crucial QOS Feature. Evolution of Switching and Routing Technologies. Technology Comparisons. Labels: The Key to Fast Forwarding. Labels for Connection-Oriented Networks. The Protocol Stacks. The X.25 Legacy. Summary.
4. X.25
Major Features of X.25. X.25 Virtual Circuit and Connection Options. Permanent Virtual Circuit (PVC) Operations. Switched Virtual Call (SVC) Operations. Fast Select Operations. Call Refusal. X.25 Packets. The General Format Identifier (GFI) Field. The Packet Identifier. Data Packets. Flow Control and Reject Packets. Diagnostic Packet. Interrupt Packet. Registration Packet. Example of an X.25 Data Transfer. The X.2 Recommendation. The X.25 QOS Operations: Facilities. Calls Barred Facilities. Closed User Group (CUG) Facilities. Reverse Charging Facilities. Network User Identification (NUI) Facilities. Charging Facility. Non-Standard Packet Sizes. Non-Standard Window Size Facility. Example of Facility Negotiations. Throughput Facility. Transit Delay and Indication Facility. Packet Retransmission Facility. Extended Packet Sequencing. Hunt Group Facility. Call Redirection and Deflection Facilities. Online Facility Registration Facility. Recognized Private Operating Agencies (RPOA) Facility. Summary.
5. Frame Relay.
Frame Relay Features. The Frame Relay Frame. Congestion Notification. Discard Eligibility. The CIR. Flow Control and Congestion Management. The CIR Revisited. The Bellcore Model. Committed and Burst Rate Management. Measurement at Intervals. Examples of Bc and CIR Operations. Relationship of CIR, Frame Size, and Link Speed. CIR and Tc. Guidelines on Use of FECN and BECN. FECN Usage. BECN Usage. Use of Windows. Other QOS Operations and Measurements. Throughput. Transit Delay. Virtual Circuit Transit Delay. Residual Error Rate (RER). Emission and Discard Priorities. Other Parameters. Other Frame Relay Specifications. The Consolidated Link Layer Management (CLLM) Specification. Switched Virtual Calls (SVCs). Asymmetrical QOS. The Other SVC Messages. Message Format. Additions to Frame Relay Operations. Fragmentation. Voice over Frame Relay (VoFR). Multilink Frame Relay (MFR). Multicasting. Frame Relay Forum's Service Level Definitions. SL Measurement Domains. The SL Parameters and Algorithms. Summary.
6. ATM.
ATM Features. ATM Specifications. The Anchorage Accords. The ATM Cell. Service Classes and the AAL. The AAL Data Units. Voice Support in ATM. Protecting the Connection. Performance Parameters. Congestion, Traffic Control, and Connection Admission Control. QOS Measurements and Degradation Factors. Traffic Shaping. Cell Emission for CBR Traffic. Connection Admission Control (CAC). Usage Parameter Control (UPC). Virtual Scheduling and Continuous-State Leaky Bucket Algorithms. Basic Concepts of the Leaky Bucket. Generic Cell Rate Algorithm (GCRA). Examples of the Leaky Bucket Operation. The ARB and UBR Service Classes. Approaches to ABR Implementations. ATM Forum ABR Operations. Performance Management. Using Connections on Demand to Negotiate QOS. Connection Management Messages. Other Signaling Messages. Summary.
7. Internet QOS Protocols.
Why IPv6? Scarcity of QOS in IPv4 and IPv6. Summary of Changes. The IPv6 Address. The IPv6 Datagram. IPv4 and IPv6 Headers. IPv6 Extension Headers. Fragmentation Header. Hop-by-Hop Options Header. Security Extension Headers. Routing Header. Destination Options Header. Internet Control Management Protocol (ICMP) for IPv6. Interworking IPv4 and IPv6. TCP and its Effect of QOS. How TCP Handles User Traffic. Interactive Traffic. Bulk Traffic. Example of TCP Traffic Accounting Operations. The TCP Timer. Timer Values. The Nagle Algorithm. Slow Start. Role of UDP in the QOS Picture. Role of Multicasting, RTP, RTCP, and RSVP in the QOS Picture. Summary.
8. Differentiated Services (DiffServ).
DiffServ Architecture. DiffServ: Control Plane and Data Plane. Comparison of QOS Technologies. DS Domains. DS Regions. Traffic Classification and Conditioning. Classification Operations. Metering Operations. Average Rate Meter. Exponential Weighted Moving Average (EWMA) Meter. Token Bucket Meter. Representations of the Meters. More Ideas on Marking and Shaping Operations. Another Look at the Traffic Conditioning Block (TCB). The DS Codepoint (DSCP). DS Guaranteed Rate (GR). Assured and Expedited Forwarding PHBs. Summary.
Appendix 8:A Differentiated Services (DiffServ).
9. IP-Based Layer 2 and 3 Switching and Routing.
Label Switching. Assigning Labels. A Switching/Routing Taxonomy. What Is Next? Position of Protocols. Encapsulation Headers. Summary.
10. Internetworking IP, X.25, Frame Relay, and ATM.
ATM vs IP. Internetworking Frame Relay and ATM. Network Interworking and Service Interworking. Comparison of Frame Relay and ATM. AAL 5 Operations for Frame Relay Support. Mapping QOS Between ATM and Frame Relay. Congestion Management. Mapping Frame Relay and ATM Connection Identifiers. Correlation of SVC Operations. Mapping the Congestion Notification Bits. Discarding Frames or Cells. Segmentation and Reassembly (SAR) Functions. Sequencing Operations. Mapping QOS between Frame Relay and ATM. ACKs and NAKs. Encapsulation Rules. IP and FR/ATM. Summary. Abbreviations.
Index.